The present invention relates to an engine control device, and particularly to an engine control device which controls an engine based on an operating state of a vehicle.
Conventionally, it is known that devices which control the behavior of a vehicle to the safe side when the behavior of the vehicle becomes unstable due to a slip etc. (such as an antiskid brake system or ABS, etc.). Particularly, it is known that devices which detect a behavior such as an understeering or an oversteering occurs on the vehicle during cornering etc. of the vehicle, and give wheels a suitable deceleration so that the behavior is controlled.
Meanwhile, JP2011-088576A discloses a vehicle movement controller which adjusts a deceleration during cornering to adjust a load applied to front wheels which are steerable wheels so that a series of vehicle operator's operations (breaking, steering-in, accelerating, steering-back, etc.) during cornering of a vehicle in a normal traveling state are natural and stable, unlike the control described above for a safety improvement in the traveling state where the behavior of the vehicle becomes unstable.
Furthermore, JP2014-166014A discloses a behavior control device for a vehicle which reduces a driving force of the vehicle according to a yaw-rate related amount corresponding to an operator's steering operation (e.g., yaw acceleration) to quickly decelerate the vehicle when the operator starts the steering operation so that a sufficient load is quickly applied to the front wheels which are steerable wheels. According to this behavior control device, since a frictional force between the front wheels and the road surface increases, and a cornering force of the front wheels increases by quickly applying the load to the front wheels when the steering operation is activated, a turnability of the vehicle in an early stage of curve entry improves, and a response to the steering-in operation improves. This achieves a vehicle behavior just as the operator intended.
It is known that a following travel control device which follows a vehicle after a preceding vehicle as one of driving support devices in order to ease operational burden of the operator. This following travel control device controls a driving force in order to accelerate or decelerate the vehicle so that a distance between two cars is kept constant.
The vehicle behavior control device disclosed in JP2014-166014A controls the driving force of the vehicle to be quickly reduced according to a steering operation, in order to accurately achieve a vehicle behavior which the operator intended.
The control of the driving force by the following travel control device competes with the control of the driving force according to the steering operation by the vehicle behavior control device disclosed in JP2014-166014A. For this reason, the cornering force of the front wheels cannot fully be increased by quickly applying the load to the front wheels unless the driving force control of the vehicle in response to the operator's steering operation is appropriately performed. Therefore, a sufficient response cannot be secured for the steering-in operation. That is, the vehicle behavior which the operator intended cannot accurately be achieved.